British fungus-flora. A classified text-book of mycology. By George Massee.

3

British fungus-flora. A classified text-book of mycology. By George Massee.

4

A handbook of the fungus diseases of West Indian plants.

1910

A handbook of the fungus diseases of West Indian plants.

1910

Genome of an arbuscular mycorrhizal fungus provides insight into the oldest plant symbiosis.

The mutualistic symbiosis involving Glomeromycota, a distinctive phylum of early diverging Fungi, is widely hypothesized to have promoted the evolution of land plants during the middle Paleozoic. These arbuscular mycorrhizal fungi (AMF) perform vital functions in the phosphorus cycle that are fundamental to sustainable crop plant productivity. The unusual biological features of AMF have long fascinated evolutionary biologists. The coenocytic hyphae host a community of hundreds of nuclei and reproduce clonally through large multinucleated spores. It has been suggested that the AMF maintain a stable assemblage of several different genomes during the life cycle, but this genomic organization has been questioned. Here we introduce the 153-Mb haploid genome of Rhizophagus irregularis and its repertoire of 28,232 genes. The observed low level of genome polymorphism (0.43 SNP per kb) is not consistent with the occurrence of multiple, highly diverged genomes. The expansion of mating-related genes suggests the existence of cryptic sex-related processes. A comparison of gene categories confirms that R. irregularis is close to the Mucoromycotina. The AMF obligate biotrophy is not explained by genome erosion or any related loss of metabolic complexity in central metabolism, but is marked by a lack of genes encoding plant cell wall-degrading enzymes and of genes involved in toxin and thiamine synthesis. A battery of mycorrhiza-induced secreted proteins is expressed in symbiotic tissues. The present comprehensive repertoire of R. irregularis genes provides a basis for future research on symbiosis-related mechanisms in Glomeromycota.

Aspergillus fumigatus fungus ball in hospitalized patients with chronic pulmonary disease: usefulness of double immunodiffusion test as a screening procedure

Double immunodiffusion (DID) was used as a screening test for the diagnosis of aspergillosis. Three hundred and fifty patients were tested, all of them referred from a specialized chest disease hospital and without a definitive etiological diagnosis. When DID was positive addtional information such as clinical history and radiographic findings were requested and also surgical specimens were obtained whenever possible. Specific precipitin hamds for Aspergillus fumigatus antigen were found in 29 (8.3%) of 350 patients sera. Nineteen (65.5%) of the 29 patients with positive serology were recognized as having a fungus ball by X-rays signs in 17 or by pathological examination in 2 or by both in 8 patients. This two-year prospective study has shown that pulmonary aspergillos is a considerable problem among patiens admitted to a Chest Diseases Hospital, especially in those with pulmonary cavities or bronchiectasis.

A stepwise protocol to coat aAPC beads prevents out-competition of anti-CD3 mAb and consequent experimental artefacts.

Artificial antigen-presenting cells (aAPC) are widely used for both clinical and basic research applications, as cell-based or bead-based scaffolds, combining immune synapse components of interest. Adequate and controlled preparation of aAPCs is crucial for subsequent immunoassays. We reveal that certain proteins such as activatory anti-CD3 antibody can be out-competed by other proteins (e.g. inhibitory receptor ligands such as PDL1:Fc) during the coating of aAPC beads, under the usually performed coating procedures. This may be misleading, as we found that decreased CD8 T cell activity was not due to inhibitory receptor triggering but rather because of unexpectedly low anti-CD3 antibody density on the beads upon co-incubation with inhibitory receptor ligands. We propose an optimized protocol, and emphasize the need to quality-control the coating of proteins on aAPC beads prior to their use in immunoassays.

Naturally acquired antibodies against the major merozoite surface coat protein (MSP-1) of Plasmodium falciparum acquired by residents in an endemic area of Colombia

A preliminary baseline epidemiological malaria survey was conducted in the village of Punta Soldado, Colombia. Parasite prevalence and density as well as serological data were obtained from 151 asymptomatic children and adults. Fifty individuals were infected with Plasmodium falciparum. The mean parasite density was 184 parasites/mm3. Greater than 90 of the sample population were P. falciparum antibody positive as detected by the indirect immunofluorescent antibody test (IFAT). The enzyme-linked immunosorbent assay (ELISA) was used to detect antibodies against the major merozoite surface protein (MSP-1) of P. falciparum. In this population, anti-MSP-1 antibody concentration is acquired in an age dependent manner with equal immunogenicity to both the N- and C-terminal regions of the molecule. Infection at the time of sampling was associated with a higher anti-MSP-1 antibody concentration than that found in non-infected individuals. Further studies are planned to assess the role of immune and non-immune factors in limiting the number of cases of severe malaria seen in this population.

Molecular characterization of chromosome termini of the arbuscular mycorrhizal fungus Glomus intraradices (Glomeromycota).

The minimum chromosome number of Glomus intraradices was assessed through cloning and sequencing of the highly divergent telomere-associated sequences (TAS) and by pulsed field gel electrophoresis (PFGE). The telomere of G. intraradices, as in other filamentous fungi, consists of TTAGGG repeats, this was confirmed using Bal31 nuclease time course reactions. Telomere length was estimated to be roughly 0.9 kb by Southern blots on genomic DNA and a telomere probe. We have identified six classes of cloned chromosomal termini based on the TAS. An unusually high genetic variation was observed within two of the six TAS classes. To further assess the total number of chromosome termini, we used telomere fingerprinting. Surprisingly, all hybridization patterns showed smears, which demonstrate that TAS are remarkably variable in the G. intraradices genome. These analyses predict the presence of at least three chromosomes in G. intraradices while PFGE showed a pattern of four bands ranging from 1.2 to 1.5 Mb. Taken together, our results indicate that there are at least four chromosomes in G. intraradices but there are probably more. The information on TAS and telomeres in the G. intradicies will be essential for making a physical map of the G. intraradices genome and could provide molecular markers for future studies of genetic variation among nuclei in these multigenomic fungi.

Segregation in a mycorrhizal fungus alters rice growth and symbiosis-specific gene transcription

Arbuscular mycorrhizal fungi (AMF) form symbioses with the majority of plants, improving plant nutrition and diversity. Evidence exists suggesting that AMF contain populations of genetically different nucleotypes coexisting in a common cytoplasm. This potentially has two important consequences for their genetics. First, by random distribution of nuclei at spore formation, new offspring of an AMF could receive different complements of nucleotypes compared to the parent or siblings-we consider this as segregation. Second, genetic exchange between AMF would allow the mixing of nuclei, altering nucleotype diversity in new spores. Because segregation was assumed not to occur and genetic exchange has only recently been demonstrated, no attempts have been made to test whether this affects the symbiosis with plants. Here, we show that segregation occurs in the AMF Glomus intraradices and can enhance the growth of rice up to five times, even though neither parental nor crossed AMF lines induced a positive growth response. This process also resulted in an alteration of symbiosis-specific gene transcription in rice. Our results demonstrate that manipulation of AMF genetics has important consequences for the symbiotic effects on plants and could be used to enhance the growth of globally important crops.

Occurence of larval Culicidae (Diptera) in water retained in Aquascypha hydrophora (Fungus: Stereaceae) in Central Amazônia, Brazil

The community structure of insects, especially mosquito larvae, in water held in the fungus Aquascypha hydrophora (Berk.) Reid (Stereaceae) is reported. The study was done in the Adolpho Ducke Forest Reserve, 26 km east of Manaus, AM, Brazil, from September 1998 through November 1999. The most abundant entomofauna were immature Culicidae (n = 121) 91.7%, followed by adult Dytiscidae (n = 3) 2.3%, immature Chironomidae (n = 5) 3.8% and immature Tipulidae (n = 3) 2.3%. Culicidae associated with A. hydrophora comprised species of the subfamilies Anophelinae and Culicinae.

Oviposition response of the mosquito, Culex quinquefasciatus to the secondary metabolite(s) of the fungus, Trichoderma viride

Secondary metabolites produced by Trichoderma viride, a deuteromycetes fungus, under submerged culture condition were formulated and evaluated for oviposition attractancy against gravid females of Culex quinquefasciatus mosquito. At a concentration of 10 µg ml-1 the formulation showed remarkable attractancy with an oviposition active index (OAI) of +0.52. When the oviposition attractancy of the formulation was compared with a known oviposition attractant, p-cresol, both at 10 µg ml-1, the former was found to be more attractive to result in 70% egg laying than the later with 30% egg laying. Thin layer chromatography fractions of the secondary metabolites showed that a fraction with Rf value of 0.88 was highly active as oviposition attractant with an OAI of +0.65. Further work on identification of the active principle(s) of the microbial formulation might lead to an oviposition attractant useful in mosquito vector management.

A potent trypanocidal component from the fungus Lentinus strigosus inhibits trypanothione reductase and modulates PBMC proliferation

The fungus Lentinus strigosus (Pegler 1983) (Polyporaceae, basidiomycete) was selected in a screen for inhibitory activity on Trypanosoma cruzi trypanothione reductase (TR). The crude extract of L. strigosus was able to completely inhibit TR at 20 µg/ml. Two triquinane sesquiterpenoids (dihydrohypnophilin and hypnophilin), in addition to two panepoxydol derivatives (neopanepoxydol and panepoxydone), were isolated using a bioassay-guided fractionation protocol. Hypnophilin and panepoxydone displayed IC50 values of 0.8 and 38.9 µM in the TR assay, respectively, while the other two compounds were inactive. The activity of hypnophilin was confirmed in a secondary assay with the intracellular amastigote forms of T. cruzi, in which it presented an IC50 value of 2.5 µ M. Quantitative flow cytometry experiments demonstrated that hypnophilin at 4 µM also reduced the proliferation of human peripheral blood monocluear cells (PBMC) stimulated with phytohemaglutinin, without any apparent interference on the viability of lymphocytes and monocytes. As the host immune response plays a pivotal role in the adverse events triggered by antigen release during treatment with trypanocidal drugs, the ability of hypnophilin to kill the intracellular forms of T. cruzi while modulating human PBMC proliferation suggests that this terpenoid may be a promising prototype for the development of new chemotherapeutical agents for Chagas disease.